Psammamonas australis gen. et sp. nov. (Raphidophyceae), a new dimorphic, sand-dwelling alga

Abstract

Grant B., Waller R.F., Clementson L.A. and Wetherbee R. 2013. Psammamonas australis gen. et sp. nov. (Raphidophyceae), a new dimorphic, sand-dwelling alga. Phycologia 52: 57–64. DOI: 10.2216/12-070.1A marine raphidophyte Psammamonas australis gen. et sp. nov. was described. Clonal cultures were established from field samples collected during the summer of 2009 from Wild Dog Beach, Victoria, Australia. Cells of Psammamonas australis had two distinct morphologies, a motile swimming phase and an adhesive benthic phase. Motile cells were irregularly ellipsoid to fusiform and were 25–35 μm long and 10–15 μm wide. The cells possessed two heterokont flagella arising from a groove and five to six nonoverlapping plastids. Benthic cells were typically irregularly discoid and were strongly adhered to the substrate either as single cells or close-fitting rafts. P. australis employed amoeboid movement during both the formation and the release of the multicelled rafts. Phylogenetic analysis based on the nuclear-encoded SSU ribosomal DNA sequence as well as the morphological evidence indicated that P. australis represented a new genus.